The present invention relates generally to systems and methods for voltage margin testing of various components of an electronic system, such as a computer system. More particularly, the invention relates to the use of I2C based potentiometers to enable voltage rail variation under BMC control.
Electronic systems often include a myriad of subsystems and components that require monitoring and/or testing during development, manufacturing and/or while in use in the field to ensure their proper operation within specified operating conditions. Many of these components typically exhibit subtle failures at margins or extremes of such specified operating conditions. It is thus desirable to test the components at these margins, herein referred to as margin testing, to evaluate their reliability at the extremes of operating conditions. For example, it may be desirable to test a component by varying one or more of its operating parameters, such as, temperature, applied voltage, and/or driving frequency, over a selected range to elicit, and hence evaluate, the system's response to such parameter variability. Margin testing can also ensure that a particular design can be readily adapted to evolving changes in manufacturing processes.
For example, testing a computer system's component by systematically varying a voltage applied thereto can provide valuable information about the reliability of that component over its associated voltage tolerance range, and especially at the extremes of this range. A number of systems and methods are known in the art for performing such voltage margin testing. For example, in one such traditional method, feedback resistors in a voltage regulator are replaced in order to vary an output voltage of the regulator that is applied to one or more components for which voltage margin testing is desired. This technique is not only time consuming but it is also invasive in that one ore more resistors need to be physically replaced. Such resistor replacement may, however, lead to accidental damage of the system under test (SUT) and/or unreliable test results.
In another conventional approach, a plurality of jumpers or switches are employed to modify resistor values of feedback voltage dividers utilized in voltage regulators. This approach is, however, time consuming, and it also suffers from low granularity of available voltage variations. It further requires the use of valuable board space for incorporation of jumpers and switches.
Another conventional approach provides a voltage rail, which supplies voltage to system components, with a trim input to which an analog voltage can be applied to vary the rail's voltage. This approach, however, requires external software-controlled test equipment for supplying the analog voltage with concomitant expense and time needed for procurement and setup of the test equipment.
In yet another traditional testing technique, the internal power rails in a system under test are disconnected and an external voltage source is utilized to apply power to the rails. The external voltage, and consequently the voltage of the internal rails, can then be varied for testing. Similar to the previous traditional approaches, this technique also suffers from a number of shortcomings. For example, it requires expensive external test equipment. Further, it is invasive, and hence prone to accidental damage to SUT. In addition, the obtained test result may not accurately reflect the characteristics of the SUT.
Hence, there is a need for systems and methods that allow reliably performing voltage margin testing of components of a computer system. There is also a need for such systems and methods that allow accurate voltage margin testing without a need to physically modify the system under test.